A prior art process for the preparation of 2,6-di-tert.butylphenol comprises alkylation of phenol with an olefin in presence of aluminum phenolate.
This prior art method makes it possible to obtain 2,6-di-tertbutylphenol with a yield of 75-87% by weight, while 22-25% by weight constitute by-products, namely para-tert.butylphenol, 2,4-di-tertbutylphenol and tri-tert.butylphenol.
Known in the art is a method of preparing 2,6-ditert.butylphenol by alkylation of phenol with isobutylene in the presence of aluminium chloride under the pressure of 70 atm. (cf. U.S. Pat. No. 2,923,745). In this method the product yield is 56 to 60% by weight.
Also known is another method of preparing 2,6-di-tert.butylphenol by alkylation of phenol with isobutylene in the presence of aluminum phenolate at temperature of 150.degree. C. under a pressure of from 45 to 50 atm.
The yield of 2,6-ditertbutylphenol is 76-79% by weight. Despite the high product yield this method has disadvantages which reside in the necessity of employing sophisticated process equipment due to the use of high pressures.
It is an object of the present invention to improve the method of preparing 2,6-di-tert.butylphenol to increase the product yield with a simultaneous simplification of the process technology.